One of the Vim features I miss is nested bracketing highlighting. When your cursor is on a "),],}", it highlights the corresponding "(,[,{", & vice versa. But in recent versions or in some syntaxes (IDK which), it's losing track at less than 5 deep, highlighting obviously mismatched pairs. Sometimes, it mismatches 1 of a pair but correctly matches the other of the same pair. In this broken state, the feature is worse than useless.

Because ed(1) doesn't have this feature, it can't do it wrong.